This invention concerns electrical connectors, and more particularly waterproof dual lead connectors adapted to allow reliable, high tensile strength field splicing to be made to blasting cap leads.
In conducting blasting operations for mining, excavation, seismic testing and the like, electrically detonated blasting caps are utilized. In many situations, the blasting caps are placed adjacent to charges located in boreholes at relatively great depth, extending vertically into the earth.
In such blasting operations there are typically a large number of charges and blasting caps implaced which all must simultaneously be detonated, or the blast will not produce the desired result and a misfire of any charge requires a very costly reboring of the boreholes and emplacement and wiring of new charges.
Typically, such boreholes are below the water table such as to be flooded, so that the electrical connections thereto must be waterproof.
The leads to the blasting caps are also subjected to significant tensile stresses due to the relatively great depths of the bore holes and rough handling incidental to such operations.
A suitable splice connector for making electrical connections to the blasting cap has not heretofore been provided, which will with sufficient reliability achieve a waterproof connection which is also able to withstand the tensile stresses placed on the spliced connection in handling. For these reasons, the practice has been to provide a large inventory of blasting caps having leads of various lengths to accommodate various borehole depths.
In copending application Ser. No. 912,211, filed on Sept. 25, 1986, now patent 4,673,233, there is disclosed a high tensile strength splice connector in which overlapping lead segments to be spliced are crimped into engagement with a conductive, generally convergent body. It would be advantageous if such high tensile strength, dual lead splice connector was able to be provided not requiring the use of crimping tools.
An important consideration in the design of such connectors is the change in electrical resistance over a range of temperatures or moisture levels. Industry standards require that such changes must not be excessive to insure complete reliability in use for the above reasons.
Accordingly, it is an object of the present invention to provide an electrical connector for making a high tensile strength dual lead splice connection between pairs cf electrical leads in which the electrical resistance does not change substantially over a range of temperature or moisture conditions.